I haven't figured out how to get the "Sync Loaded Item" option in templates menu of Platform 5 to stay checked. It doesn't give me an option to save settings when I select it, and when I select it then click off the editor, it unselects. Also if I select it before loading a template, it doesn't stay checked there either. Whats going on?

WordPress 4.7.1 was released on 11th January.
It introduced a new bug that stops certain filetypes from being uploaded.
This bug unfortunately stops users from uploading SVGs with the Platform 5 builder.
In the meantime if you need to upload an SVG or have any other image upload issues then please try this plugin that bypasses the mime checks that were introduced.https://wordpress.org/plugins/disable-real-mime-check/

Link to trac ticket: https://core.trac.wordpress.org/ticket/39550
EDIT: 4.7.2 has been released without the fix. Fix is now slated for 4.7.3